As an improvement upon conventional building practices, where insulation in the form of batts or granular material is placed between framing members of a structure, this invention is directed to completely enclosing the structure with insulation. A prefabricated, thermally insulated panel is provided which comprises a lamination of exterior building material such as siding or sheathing, interior material such as drywall or finish board, with solid insulation permanently secured between them. By securing panels in abutting relationship to the complete exterior of the frame of both the walls and the roof, the entire interior of the structure is virtually within an envelope of insulating material. Furthermore, the use of solid or rigid insulating materials offers a wider choice of higher efficiency insulations than the more conventional flexible batts or particulate materials.
Laminated panels of this type are secured to the exterior of the structure by nailing. It is desirable to center the joint between adjacent panels on a beam, joist or rafter to permit both panels to be securely nailed close to their abutting edges. However, it is not always possible to do this. More often than not, the joint between adjacent panels occurs where there is no beam or stud and means must be provided to lock the panels together and to keep their surfaces in the same plane.
This is accomplished by interlocking two panels together with splines which run lengthwise of the butting edges of the two panels. A single spline engages the exterior siding and a second spline engages the interior drywall of the two abutting panels along their interior or insulation engaging surfaces, i.e. on the inside of the outer laminae of the panel. Screws are then driven through the exterior and interior laminae adjacent their edges and into the splines.
The splines are accommodated within grooves routed or milled out of the insulation material, half of one spline being accommodated in one panel and the other half of the spline being accommodated with a mating groove in the adjacent panel.